MMP9 and type 1 diabetes mellitus: In this study, we found that D-4F treatment in T1DM rats subjected to stroke significantly decreases BBB leakage, increases tight junction protein expression, and reduces inflammatory factor expression such as MMP9, TNFα and NFκB in the ischemic brain, as well as improves functional outcome compared to PBS treated T1DM stroke rats at 48 hours after stroke.